1. Technical Field
The following description relates to an organic light emitting display device and method of manufacturing the same, and more particularly, to a bottom emission type organic light emitting display device in which a pattern and an outer line of a display panel are not shown.
2. Discussion of the Related Art
Recently, as we increasingly become an information-oriented society, the field of display devices, which visually express an electrical information signal, is rapidly advancing. Flat panel display (FPD) devices, having excellent performance in terms of thinness, light weight, and low power consumption, have been developed. Examples of the FPD devices include LCD devices, plasma display panel (PDP) devices, field emission display (FED) devices, organic light emitting display (OLED) devices, etc.
In particular, the OLED devices are self-emitting devices. In comparison with other FPD devices, the OLED devices have a fast response time, high emission efficiency, high luminance, and a broad viewing angle. Moreover, a high resolution and a large screen are realized. Therefore, the OLED devices are attracting much attention as next-generation display devices.
The OLED devices include an organic emission layer which is formed between two electrodes (a cathode electrode and an anode electrode). An electron and a positive hole are respectively injected from the two electrodes into the organic emission layer, and an exciton is generated by combining the electron with the positive hole. The OLED devices use the principle that light is emitted when the generated exciton drops from an excited state to a ground state.
The OLED devices are categorized into passive matrix OLED devices and active matrix OLED devices, depending on a driving type. The passive matrix OLED devices include a plurality of pixels, which are arranged in a matrix type, without including a thin film transistor (TFT). In the passive matrix OLED devices, power consumption is higher and resolution is more limited than for the active matrix type.
On the other hand, the active matrix OLED devices have a structure in which a plurality of TFTs are respectively formed in a plurality of pixels which are arranged in a matrix type. Each of the plurality of pixels is driven according to a switching operation of a TFT and a voltage charged into a storage capacitor Cst.
Therefore, the active matrix OLED devices have low power consumption and a high resolution in comparison to the passive matrix organic light emitting display devices. An active matrix OLED device is suitable for a display device requiring a high resolution and a large area. For reference, in the following disclosure, an active matrix OLED device is generally referred to as an OLED device.
FIG. 1 is a diagram illustrating a non-display area and an active area of a related art OLED device.
With reference to FIG. 1, the related art OLED device includes a display panel 1 and a driving circuit unit (not shown) that drives the display panel 1. The display panel 1 includes an array substrate 10 in which a plurality of organic light emitting diodes (OLEDs) and a plurality of pixel circuits for emitting light from the OLEDs are formed, an optical film 20 adhered to a rear surface of the array substrate 10, and an encapsulating substrate 50 that encapsulates the OLEDs.
Here, the organic light emitting display device of FIG. 1 displays an image in a bottom emission type. Therefore, the optical film 20 is adhered to the rear surface of the array substrate 10, and a polarizing film, a film-type patterned retarder (FPR), or a three-dimensional (3D) polarizing film is applied as the optical film 20.
The display panel 1 includes an active area, in which a plurality of pixels 30 are arranged in a matrix type and an image is displayed, and a non-display area. The plurality of pixels 30 are formed in the active area. In order to display a full-color image, a red sub-pixel R, a green sub-pixel G, a blue sub-pixel B, and a white sub-pixel W constitute one pixel 30. Each of the sub-pixels includes an OLED and a pixel circuit, which includes a driving thin film transistor (TFT), a scan TFT, and a sensing TFT.
The driving circuit unit includes a data driver, a gate driver, a timing controller, and a power supply. A plurality of pads (not shown), a plurality of link lines 40, and a plurality of log lines (not shown), which are connected to the driving circuit unit and supply a driving signal to each of the plurality of pixels, are formed in the non-display area. The plurality of link lines 40 and the plurality of log lines are for supplying the driving signal, and are arranged at certain intervals in the non-display area (i.e., an outer portion of the display panel 1) of the display panel 1.
FIG. 2 is a diagram illustrating a problem in which metal lines and a pattern of a space are shown due to reflection of light.
With reference to FIG. 2, external light passes through the optical film 20, and then is reflected by the plurality of link lines 40 and the plurality of log lines. In this case, there is a problem in which metal lines (the link lines and the log lines) and a pattern of spaces are shown due to a space between the plurality of link lines 40 and the plurality of log lines. For this reason, a pattern of the lines formed in the non-display area is visible to a user.
Moreover, in the bottom emission type organic light emitting display device, the encapsulating substrate 50 encapsulates a front surface of the array substrate 10. In this case, the encapsulating substrate 50 covers an entirety of the active area, but covers only a portion of the non-display area. Therefore, an amount of light reflected from an area where the encapsulating substrate 50 is formed differs from an amount of light reflected from an area where the encapsulating substrate 50 is not formed. For this reason, a pattern of the lines formed in the non-display area is very visible to a user.
In the OLED device that displays an image in the bottom emission type, it is desired to increase a sense of beauty by realizing a borderless panel, but since the pattern of the lines formed in the non-display area is recognized, an external aesthetic appearance of the organic light emitting display device is degraded.